2000 Polaris 500 Sportsman, starts and runs fine, but when I try to accelerate it bogs down and backfires like when you use reverse without pushing the overrride button. Plug looks good, fuel looks good, air filter looks good, anyone ever had this issue?

 

maybe the cam lobs are worn. on the older yr 500's some had the cams wear on then making them run crappy. just an idear.

 

Before going to the cam check the secondary buttons

 

Also make sure the ETC is adjusted correcly , about 4 inches from the thumb throttle adjust slack so there is only 1/8 of an inch.

 

ETC works fine, thanks, what are the secondary buttons?

 

On the secondary clutch (Driven) Check the clutch belt too!

 

my 98 trailboss is starting to do that but it is only when i push the throttle half or more and it will do it when i have it in nuteral and i rev it up. is sounds just like you described. i think it seems like an exaust leak but my brother tells me it might be a bad spark plug. i still have to cheak a few things

 

i have had same thing with my 250 have been tring to find the cause for 3 weeks, have rebuilt the carb 3 times,cleaned the gas tank filters, checked the plug checked the air tubes, checked spark even went as far as putting a rubber hose over plug wire thought it was arcking, i have changed the fuel filter but i have notcied went it dsoe act up there is air bubbles in the fuel filter, mine works some times and others it won't so if some finds the answer please pass it on

 

SMOKEF
Check the vaccum diaphram i have seen many with small pin holes in them and causes this alot,take it out hold up to lite and look very careful,ive had a couple that couldnt find the hole but changed the diaphram and poof it ran like new again just my 2 cents

 

bullpark1956
do you mean the one inside the carb? I changed the belt, cause it was a little thin (according to the book) with no change. i guess i have a spare now. my next step is to check the gas. i also noticed it's running a little hot (the fan comes on more often and sooner than before). this may be related, so i'll probably ask the local mechanic if this sounds like anything he's encountered before. just don't want to bring it in (pride, puzzle,$$$, etc.)